UnitTestFrameworkPkg: Add -Wno-write-strings to host unit tests

Disable write strings warning for host-based unit test
builds when building modules of type HOST_APPLICATION.

Modules of type HOST_APPLICATION may compile and link code
under test into the host-based unit test. When building
GoogleTest based unit tests, the G++ compiler is used. The
G++ compiler is stricter than GCC for passing a const string
into a function parameter that is not const. This is not a
warning for GCC build of firmware code. But GoogleTest builds
that use g++ detect as a warning and that breaks the build.

The firmware code under test can not be changed, so the warning
-Wno-write-strings is added to CC_FLAGS to ignore this warning.

Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>

UnitTestFrameworkPkg/UnitTestFrameworkPkgHost.dsc.inc

@@ -71,6 +71,7 @@
   #
   # GCC
   #
+  GCC:*_*_*_CC_FLAGS       =  -Wno-write-strings
   GCC:*_*_IA32_DLINK_FLAGS == -o $(BIN_DIR)/$(MODULE_NAME_GUID) -m32 -no-pie
   GCC:*_*_X64_DLINK_FLAGS  == -o $(BIN_DIR)/$(MODULE_NAME_GUID) -m64 -no-pie
   #